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Jessica Ennis of Great Britain competes in the Women's Heptathlon High Jump. Ennis kicked off the track and field action by crushing records in the 100-meter heptathlon hurdles.

Updated at 1:05 PM EDT on Friday, Aug 3, 2012

A day after Michael Phelps made history yet again in the pool with his dramatic victory over long-time rival Ryan Lochte, eyes are turning Friday to London's Olympic Stadium where the first day of track and field is underway.

Britain's sweetheart Jessica Ennis kicked off the track and field action by crushing records in the 100-meter heptathlon hurdles. She ran the race in 12.54 seconds, which tops the 24-year-old Olympic record (12.69) and 7-year old world record (12.62). Fans packed in the 80,000-seat stadium erupted in cheers and waved the Union Jack for their hometown girl.

Golden Athletes of the London 2012 Games

USA's Sanya Richards-Ross, who has rebounded from health issues that have plagued her over the last two years, qualified Friday for the 400m semi-finals on a track that had just been doused by a powerful downpour. Her time of 51.78 was nearly a second behind Christine Ohuruogu, a crowd favorite from London's East End, who ran neck-and-neck with Richards-Ross in Beijing before passing her for the gold.

Richards-Ross took bronze in the 2008 event and also scored a gold in the 4x400-meter relay team, as she did in 2004. But she has yet to win a gold medal for an individual event, which she hopes to do at the London Games.

Celebrities Invade the Olympics

"They say the third time is the charm, so I'm hoping that holds true for me," Richards-Ross told running site Spiked Up. "My training is exactly where I want it to be, so I'm hoping to have my best race of the season here at the Olympics."

Friday morning both Richards-Ross and Ohuruogu were bested by another American, Francena McCorory, who finished her debut Olympic race in 50.78 seconds.

On the men's side, USA's Michael Tinsley called the track "lightning fast" after qualifying for the 400-meter hurdles with a time of 49.13, the top time in his heat.

At London's sprawling ExCel Center history was made when a female athlete from Saudi Arabia—one of just two women from the Gulf state competing in the Games—took the judo mat. Wojdan Ali Seraj Abdulrahim Shahrkhani wore a judo dress and a tight-fitting black hat to fight Puerto Rico's Melissa Mojica, according to The Associated Press. Though she lost after just 82 seconds, the crowd celebrated her presence at the Games, which wasn't guaranteed until an eleventh hour compromise between Saudi officials and Olympic organizers granted her the right to wear a modified hijab.

Qatar also sent women to the Games for the first time this year including a 17-year-old runner who was unable to complete her debut race Friday morning. Noor Hussain Al-Malki, dressed in long sleeves, full leggings and a headscarf made it just 15 meters into the 100-meter race before collapsing on the track and grabbing her leg.

USA's top-seeded tennis duo, Mike and Bob Bryan, beat France's Julien Benneteau and Richard Gasquet, 6-4, 6-4 in the semifinals of men's doubles at Wimbledon, assuring them of at least a silver medal at the London Games, according to the AP. They won bronze in Beijing.

Later, men's shot put gets underway at 3.30 p.m. ET. The event will be streamed live on NBCOlympics.com and replayed on NBC at 8 p.m. ET/PT. The U.S. has three strong medal contenders in Reese Hoffa, Christian Cantwell and Ryan Whiting – all of whom own world championship titles. Hoffa posted the world’s best throw at the Olympic trials with a heave landing at the 72 feet, 2¼ inches mark.

Hoffa, 34, lives in Athens, GA. and told USA Today that the London Games will probably be his last since he and his wife Renata plan on starting a family. He went into the 2008 Olympics as world champion but finished in seventh, a ranking he attributes to being over-extended in the media and the public's expectation of a gold medal. "I'm starting at zero until I prove myself at the Olympic Games," said Hoffa. "This is do or die. If I want to end my career Olympic-wise with a medal, I gotta get after it."

Over on the track, the tiny titans of distance running will clash in the women's 10,000m race broadcast live on NBC at 4:25 p.m. Kenyan Vivian Chruiyot and Ethiopian Tirunesh Dibaba are expected to lead the pack which includes U.S. runners Lisa Uhl and Amy Hastings.

Debaba produced a double feat at the 2008 Games in Beijing when she collected both the 5,000m and 10,000m titles. In their 17 career meetings that go back more than a decade to 2001, Cheruiyot, 33, has only finished ahead of Debaba, 26, on two occasions. But the confident Cheruiyot has the gold firmly in her sight, telling Kenya's Capital FM Sports "I know this is my year and I want to tell Kenyans to pray for us because we will lift our flag high since we are going in to battle."

Back in the pool, Phelps will do his best to make a splash as he competes in the 100M butterfly at 2:30 p.m. ET, his last individual event. The race comes on the heels of his history making three-peat win in the 200m individual medley Thursday. He could pull off an unprecedented second three-peat with a triumph Friday. He is expected to finish his Olympic career Saturday with the men's 4x100m medley relay.

The men’s 50m freestyle also will be streamed live at 3:09 p.m. ET. Known as the “splash and dash,” the fastest event in swimming is notoriously hard to predict, but Brazilian Cesar Cielo has done his best to take the mystery out of the results, winning this event in Beijing as well as at the two world championships since. American Cullen Jones will be close in Cielo's wake, if not ahead after Thursday qualifying heat. The 2008 relay gold medalist tied Cielo for the fastest time.

Other events Friday include:

Live coverage of the U.S. women’s water polo team vs. China at 2:40 p.m. on NBC. The Americans have earned a medal at each of the three Olympics since women’s water polo made its Olympic debut in 2000, but have never won gold.

In women’s volleyball, Team USA, which faces an up-and-coming Serbia squad tonight, is favored for its first ever Olympic gold medal. It would be the second in a row for the team’s head coach Hugh McCutcheon, who coached the U.S. men to the Olympic title in 2008. It will be replayed on NBC from 8 p.m. ET/PT.

NBC will broadcast live coverage of beach volleyball’s crucial elimination rounds from historic Horse Guards Parade beginning at 4 a.m. ET and continuing throughout the day.